1. Field of the Invention
The present invention relates generally to computer networks, and more particularly but not exclusively to computer network security.
2. Description of the Background Art
The widespread accessibility of public computer networks, such as the Internet, has enabled users from around the world to efficiently communicate with one another and access vast amounts of information. For example, a user employing a client computer with a Web browser can log onto the Internet to download files, send and receive e-mails, read web pages from websites, and so on. Unfortunately, the Internet not only attracts legitimate users but those with malicious intentions as well.
Malicious users on the Internet, also collectively referred to herein as “hackers,” write and propagate malicious codes, such as computer viruses, worms, Trojans, and spyware, indiscriminately send junk e-mails (“spam”), and perpetuate frauds and denial of service attacks. Hackers also hijack legitimate websites, steal Internet Protocol (IP) addresses, and redirect users to malicious websites. The malicious activities of hackers, and the damages they cause, are well-known. Antivirus (which includes anti-spyware and anti-spam) software and firewall technologies may be employed as protective measures against malicious activities. However, while these protective measures are effective for the most part, they need to be augmented or improved to combat the ever increasing sophistication of hackers.